Illuminated dial



March 10, 1942. w GARDINQR 2,275,621

ILLUMINATED DIAL Filed Sept. 10, 1940 NTOR ATTORN EY Patented Mar. 10,

to International Business Machines Corporation, New York, N. Y., acorporation of New York Application September 10, 1940, Serial No.356,148 3 Claims. (01. 240-4.!) This invention relates to a clock dialstructure and means for illuminating the same. I

The general objectof the instant invention is to provide improvedillumination for a clock dial by special arrangem nt of a light-sourceand light directing surfaces to effect a substantially even distributionof light over the dial.

More specifically, an object of the invention resides in the provisionof illuminated gas-filled tubing located between the dial and the handsof the clock to prevent the clock hands from casting shadows on thesurface of the dial.

Another object is to provide a clock dial having a special curvature toaid in reflecting the light from a source mounted behind the clock handsand adjacent the central portion of the dial.

It is also an object to provide an opal glass disk novelly mountedbetween the light source and the, clock hands for diffusing the lightpassing therethrough so as to lend a more pleasing ap-. pearance to theilluminated clock dial.

The invention contemplates employing a dish shaped dial for aiding indirecting the light more eifectively from a circular tube filled with asuitable gas, such as neon, and mounted directly in front of the centralportion of the dial. An opal glass disk is placed in front of the tubeand the clock hands are located in front of the disk. With'thisarrangement, part of the light dlifuses through the disk and part of thelight strikes the curved surface of the dial and is reflected outwardly.In'view of the fact that the clock hands are mounted in front of thelight source and the disk, there can be no shadows .cast by these handsin. the direction of the dial. The rear lighting of the clock handsmakes their position and identification more readily determinable at aglance.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the accompanying drawing,which discloses, by way of example, the principle of the invention andthe best mode, which has been contemplated, of applying that principle.In the drawing:

Fig. 1 is a face view of the clock.

Fig. 2 is a section taken on line 2-2 of Fig. 1.

Fig. 3 is a sectional detail view showing the connection between thedial and a rim which also holds the customary glass cover protecting theclock face.-

Referring now to the drawing, It represents a drum containing thenecessary clock mechanism for driving stub shafts II and I2 to which arethe center of the dial. In

attached an hour hand ll and a minute hand I4,

, ture.

respectively. The clock mechanism in itsel forms no part of the presentinvention.

v A plate i5, integral. with the right end of the drum as viewed in Fig.2, is provided with mountlng brackets i5 bolted to the plate at spacedintervals around its periphery. Bolts H, which are employed to connectthe brackets with the plate, also serve to fasten an opal glass disk IEto the supporting plate IS with the cooperation of nuts l9 and 20. Diskis is formed with a central hole to provide clearance for shafts ii andii. The thicknesses of brackets 16 and of the nuts 20 cause a space tobe left between the disk [8 and the supporting plate i5 which helpsprovide clearance for a circular glass tube 2| placed immediately behindthe disk l8 and directly in front of a clock dial 22.. The tube 2| isfilled with gas, such as neon, and is illuminated in a well knownmanner'by application of a suitable difference of potential to terminalmembers 2m and 2lb which pass through holes in the dial 22 and helpsupport the tube in the position shown in the drawing. The clock dialitself is secured to the brackets i 6 by bolts cooperating with nuts 24.A circular ring 25 serves as a backing for the dial to strengthen thebolted connections with the brackets.

The clock dial 22 is made concave, resembling in shape anordinary dish.The reason for pro viding such a curvature to the dial is'to improve thereflection of light rays from illuminated tube 2| which impinge on thesurface of the dial. A considerably larger portion of the light from thetube reachesdial 22 directly by virtue of its curvature than would fallon a flat dial mounted at the same place.

A suitable rim 25 is provided to cover the outer edges of the dial andof a protective glass 28. The glass and the dial areclamped together atthe edges by the cooperation between the front of the rim 25 andspringclip 21 carried by the run. A substantially even distribution oflight on the dial is-obtained by the above described struc- The lightwhich tends to come directly out to the front from tube 2| is difl'usedby the opal disk I 8. The light which tends to directly seek out the rim25 is intercepted by the curved surface of the dial 22. By locating thelight source in the manner shown, rather than in the rim as iscustomarily done with a tubular light source, lsto greatly reduce theshaded portion around I the arrangement presentedherein, the lightsource is considerably closer to the center of the dial and the light ison the clock dial.

softened by diffusion. As the clock hands it and il rotate in front ofthe light source and the diffusing disk, they cannot cause shadows tofall While there has been shown and described and pointed out thefundamental novel features of the invention as applied to a singlemodification, it will be understood that various omissions andsubstitutions and changes in the form and deillustrated and in itsoperation may be made by those skilled in the art without departing fromthe spirit of the invention. It is the intention therefore to be limitedonly as indicated by the scope of the following claims.

What is claimed is:

1. A clock case construction comprising, in combination, a supportingplate at the rear of said case, a concave dial secured to said plate, aluminous gas tube positioned about the center of the dial andintermediate the center of the dial and its edges, an opalescent elementcarried by the supporting plate and spaced therefrom so as to be locatedimmediately in front of the tube, and clock hands supported in front ofthe element for cooperation with the dial.

screen 2. A clock case construction comprising. in combination, asupporting plate at the rear of said case. a concave dial secured tosaid plate, a circular tube containing luminous gas positioned about thecenter of the dial, the diameter of the dial being substantially greaterthan the diameter of the circle formed by the tube, an opalescentmaterial carried bythe supporting plate and spaced outwardly therefromso as to be located in front of the luminous gas tube, and clock handssupported in front of the material for cooperation with the dial.

3. In combination, a supporting plate, a concave clock dial fastened tosaid plate, a luminous gas tube located in front of the dial andadjacent the central portion of said dial, an opalescent materialcarried by the supporting plate spaced therefrom a distance suiilcientto locate the material in front of the tube, clock hands supported infront of said material and cooperating with the dial, a glass panel infront of the hands for covering the dial, and a rim around the edge ofthe dial for holding the outer edges of the materlal against said dial.

ELLIOTT W. GARDINOR.

